Rubber solution must be made from indiarubber-which lias not been vulcanised; Para rubber is considered best for the purpose. The rubber should be cut. into thin shavings with a very sharp, wet knife. The shavings may be dried, then placed iu a dry, wide-mouthed bottle, and covered with benzene (coal-tar naphtha) or carbon bisulphide. Benzene is preferable, as it does not smell quite so strong as carbon bisulphide. The bottle should be tightly corked, placed in a warm place, shaken from time to time, and more solvent added as the rubber swells. One ounce by weight of rubber will take from 15 oz. to 20 oz. by measure of the benzene. This solution will be found suitable for patching a mackintosh or for use in places where rain penetrates, but as a dressing for re-waterproofing it will not stand.